1. Field of the Invention
The present invention relates to a switch structure and a display device including such a switch structure.
2. Description of the Related Art
There has been demand in recent years for liquid crystal display devices that have narrower bezels and that are thinner in the depth direction. To this end, the front cabinet that encloses the liquid crystal panel is formed so as to make the dimensions smaller in the up/down, left/right, and depth directions when the liquid crystal display is viewed from the front. There are techniques for providing an operation key for performing various types of setting of the liquid crystal panel on a front cabinet with such small dimensions, including the technique described in Japanese Patent Application Laid-Open Publication No. 2007-11012.
FIGS. 13A and 13B are diagrams showing the structure of conventional operation keys. Note that in FIGS. 13A and 13B, Y1 indicates the direction toward the front, while Y2 indicates the direction toward the rear.
In this example, a cover 300 is attached to a front cabinet 11 as shown in FIG. 13A so as to be able to close and open. A plurality of operation keys 400 are provided on the front surface of the cover 300. FIG. 13B shows a state in which the cover 300 is open, with a substrate 200 being secured by a rib 500 such that switches 203 face in the forward direction. With this constitution, the switches 203 are pressed if the operation keys 400 are pressed with the cover 300 in the closed state.
However, with the method for attaching the operation keys 400 to the cover 300 in this manner, the cover 300 needs to be separately provided, which is a factor leading to increased costs.
Meanwhile, there is a method for forming operation keys without adding any separate components. FIG. 14 is a side view showing an operation key that is formed without adding any separate components. Note that in FIG. 14, X1 indicates the direction to the left, while X2 indicates the direction to the right. Furthermore, Y1 indicates the direction toward the front, while Y2 indicates the direction toward the rear. Moreover, Z2 indicates the downward direction.
In FIG. 14, a plurality of ribs (not shown) are provided on the lower portion of the front cabinet 11 in order to hold the substrate 200. The substrate 200 is held by the various ribs such that it is sandwiched in the thinnest direction of the substrate 200.
Openings 1110 are formed in the front cabinet 11. The switches 203 disposed on the substrate 200 are exposed from the openings 1110. As will be described later, each switch 203 includes a switch main body part 201 that is pressed in by an operation key 400 and a metal plate 202 that surrounds the switch main body part 201 and that has a square exterior shape.
A protruding part 401 protrudes from an end surface 1110A of an opening 1110, and the operation key 400 that receives the pressing operation by the user is formed at the tip end of the protruding part 401.
The protruding parts 401 have elasticity in the forward direction with respect to the front cabinet 11, and when the operation keys 400 are operated, the protruding parts 401 are pushed in the rearward direction in opposition to the elastic force, and the contact surfaces 400S press on the surfaces of the switch main body parts 201. Thus, the operation keys 400 are formed by effectively utilizing the narrow region of the front cabinet 11 without adding any separate components.
However, the following problems are encountered in the operation keys. FIGS. 15A-15C are diagrams illustrating the problems of the operation key of FIG. 14. Note that FIG. 15A is a plan view of the operation key 400, FIG. 15B is a perspective view of the operation key 400, and FIG. 15C is a perspective view representing the positional relationship between the protruding part 401 and the metal plate 202.
The operation key 400 is provided at the tip end of the protruding part 401 that protrudes from the opening end surface 1110A which is an end surface of an opening 1110 as shown in FIG. 15A and FIG. 15B. In addition, the switch main body part 201 and the square-shaped metal plate 202 that surrounds the switch main body parts 201 are exposed from the opening 1110.
With this constitution, when the operation key 400 is pressed, it is often the case that the upper surface of the protruding part 401 comes in contact with the metal plate 202 of the switch 203 in a state in which the operation key 400 is not solidly depressing the switch main body part 201 as shown in FIG. 15B and FIG. 15C.
In particular, in cases where the distance h from the opening end surface 1110A to the operation key 400 is not adequately secured in the protruding part 401 as shown in FIG. 16, it is difficult to press the operation key 400 against the elastic force of the protruding part 401.
Furthermore, even if one attempts to form an operation key 400 as in FIG. 17A on the front cabinet 11, on most types of front cabinets 11, there are a plurality of ribs 500 for securing the substrate 200 as shown in FIG. 17B. Typically, in order to form operation keys 400 such as in FIG. 17A with resin using molds, the molds require slide mechanisms, but a slide mechanism cannot be used when the ribs 500 are provided as in FIG. 17B.